What did Khrushchev agree to do, according to this excerpt?

Don't know exactly what you are looking for, but...

After Kennedy threatened Khrushchev with an attack, and after long hours of waiting for one to attack another,

Khrushchev finally agreed to a deal made earlier in the crisis, that deal was if the Soviet Union gave there missiles to the US then the US would remove their missiles from Turkey, that weren't as dangerous to Cuba. No one but the government knew about this deal so it looked like the soviet union had just given in.

the correct answer is b